Control system and method

ABSTRACT

The invention relates to a control system and method, particularly for providing sophisticated switching control, such as for the provision of irrigation control and/or scheduling lighting schedules, security measures, and other purposes, with respect to a site or a series of sites in an area. A method of control for a distributed event system is disclosed, the method providing control of events at one or more locations, each location associated with a programmable location controller ( 10 ) able to cause or permit a prescribed event to be carried out at that location, each location controller ( 10 ) able to receive control commands from a remote controller, each location controller ( 10 ) having at least two default settings to govern implementation of said prescribed event in case of non-receipt of commands from said remote controller. The default settings may be automatically selectable in accordance with the time, e.g. time of day, day of week and/or season of year.

INTRODUCTION

[0001] This invention relates to a control system and method,particularly for providing sophisticated switching control, such as forthe provision of irrigation management and/or scheduling lightingschedules, security measures, and other purposes, with respect to a siteor to a series of sites in an area.

BACKGROUND OF THE INVENTION

[0002] In respect of irrigation control technology, devices to start andstop irrigation cycles without human intervention (generally known, andreferred to hereinafter as ‘controllers’) are well known and are thesubject of a number of patents and patent applications. These devicessend an electric current (usually 24 vAC in horticultural, agriculturalor domestic use) to a remote solenoid valve causing that valve to open.Closure of the valve is usually effected by discontinuing the supply ofelectric current to the solenoid of the valve whereupon the valve isclosed, eg by a suitable resilient means. Most controllers are able toaccommodate a number of such valves, opening and closing them in aprogrammed succession for prescribed times on prescribed days of theweek. This series of sequential valve opening and closing—for specifiedtimes on specified days—is generally referred to as an ‘irrigationprogram’. Some—indeed many—of the known devices are capable of storingand executing more than one such program, thus adding a degree offlexibility to what may be accomplished.

[0003] A major failing of such devices is that, in general, they arecapable only of repeating the program or programs, without any abilityto respond other factors, and particularly to weather conditions, rainetc. As a result of this problem, the operation of the type ofirrigation controller described above often results in considerablewastage of water.

[0004] Some attempts have been made to tackle this problem of waterwastage due to controllers which can only repeat a predeterminedschedule. These include:

[0005] rain switches which prevent controller operation during andshortly after rain;

[0006] soil moisture measuring devices which prevent controlleroperation when soil is judged to be sufficiently moist; and

[0007] controllers which are able to schedule their operations usingmeteorological data.

[0008] One of the present inventors has previously taught methodsproviding a considerable advance on the above-mentioned techniques, asdisclosed in PCT patent applications WO-97/27733 and WO-99/48354.

[0009] In these above-mentioned methods, enabling/disabling or otherwisecontrolling the activity and/or output of a controller is usuallyperformed by means of a switch relay located in the electrical circuitbetween the controller and the solenoids of the irrigation supplyvalves. The switching coil of this relay can be energised andde-energised to control the device in which it is incorporated, in orderto achieve the local activity, (or lack thereof) required.

[0010] Such relays are typically wired to the irrigation sub-systemusing either normally closed or normally open terminals. If thesub-system is wired to the relay using normally closed terminals, thenthe activity to be controlled (ie the programmed event) will occurunless a controlling signal is received by the device incorporating therelay. If the sub-system is wired to the relay using normally openterminals, then the activity to be controlled will not occur unless acontrolling signal is received by the device incorporating the relay.

[0011] The respective modes of relay wiring have respective advantagesand disadvantages depending on:

[0012] the particular circumstance of the activity;

[0013] the time of year; and

[0014] the day of week.

[0015] With this in mind, it is dear that neither wiring configurationwill necessarily always provide the most suitable operating mode.

[0016] In this specification, where a document, act or item of knowledgeis referred to or discussed, this reference or discussion is not anadmission that the document, act or item of knowledge or any combinationthereof was at the priority date:

[0017] (i) part of common general knowledge; or

[0018] (ii) known to be relevant to an attempt to solve any problem withwhich this specification is concerned.

SUMMARY OF THE INVENTION

[0019] According to the invention in one aspect, there is provided amethod of control for a distributed event system, providing control ofevents at one or more locations, each location associated with aprogrammable location controller able to cause or permit a prescribedevent to be carried out at that location, the location controller ableto receive control commands from a remote controller, each locationcontroller having at least two default settings to govern implementationof said prescribed event in case of non-receipt of commands from saidremote controller.

[0020] Preferably, said default settings are automatically selectable inaccordance with one or more parameters, for example in accordance withtime This may be in accordance with the season of the year and/or theday of the week and/or the time of the day.

[0021] In one form of the invention, the distributed event systemcomprises an irrigation system, and each location controller isoperatively connected with at least one electrically operable watervalve to control water supply to an area associated with that location,each location controller including an electrical switch relay having twoselectable default positions, ‘fail-open’ and ‘fail-closed’.

[0022] Control commands received from the remote controller by saidlocation controller may be provided in accordance with monitoredmeteorological conditions.

[0023] In a preferred form, the default position for a locationcontroller is established as part of the power connection configurationto the electrical terminals of the at least one electrically operatedwater valve.

[0024] In one embodiment of this form of the invention, the powerconnection configuration is selectable under software control, thesoftware being remotely programmable from the remote controller to varythe functional relationship between the selection of the defaultsettings and said one or more parameters.

[0025] In another form, the power connection configuration is selectableunder hardware control, and may include a bi-polar stable relay.

[0026] The invention, then, provides a default mode alterationcapability for event enabling systems. In the example of an irrigationcontrol system, where locally programmed irrigation regulation can beoverridden in accordance with remote signals issued in response tomonitored meteorological conditions, the invention provides a preferredfailsafe functionality to the system, such that in the absence ofreceipt of said remote signals by a local irrigation controller (due,for example, to a break in the communications network to thecontroller), the irrigation event may be enabled or disabled,selectively in accordance with, say, the day of the week, season of theyear, etc. Other parameters (beyond time alone) may alternatively oradditionally be used to automatically provide the controller defaultsetting, such as locally monitored light levels, temperature, humidity,rainfall, etc.

[0027] The connection between the remote controller and the locationcontroller may be provided by way of a distributed computer network suchas the Internet, and may include wireless data transmission equipment totransmit control commands from the remote controller to the locationcontroller.

[0028] According to the invention in a further aspect, there is provideda programmable location controller for a distributed event enablingsystem controlling events at one or more locations, the controller ableto cause or permit a prescribed event to be carried out at a respectivelocation, the controller arranged to receive control commands from aremote controller, wherein the controller has at least two defaultsettings to govern implementation of said prescribed event in case ofnon-receipt of commands from said remote controller.

[0029] Preferably, the controller includes means to select said defaultsettings in accordance with one or more parameters, for example inaccordance with time. This may be in accordance with the season of theyear and/or the day of the week and/or the time of the day.

[0030] The controller may be for use with an irrigation system as saiddistributed event system, the controller operatively connectable with atleast one electrically operable water valve to control water supply toan area associated with that location, the controller including anelectrical switch relay having two selectable default positions,‘fail-open’ and ‘fail-closed’.

[0031] The controller may include a power connection configuration tothe electrical terminals of the at least one electrically operated watervalve, said configuration providing the means to establish the defaultposition.

[0032] For example, the controller may include software to establishsaid power connection configuration, and may include means to allowremote programming of said software from a remote controller to vary thefunctional relationship between the selection of the default settingsand said one or more parameters.

[0033] Alternatively, the controller may include hardware circuitry toprovide said power connection configuration, such as a bi-polar stablerelay.

[0034] According to the invention in a further aspect, there is providea programmable irrigation system including the above-mentionedprogrammable location controller and a plurality of electricallyoperable water valves operatively interconnected therewith in order tocontrol water supply to an area associated with that location.

[0035] According to the invention in a further aspect, there is provideda distributed event system including a plurality of controllers asdefined above, including means to provide control commands to saidlocation controllers automatically in accordance with monitoredmeteorological conditions.

[0036] Preferably, then, said remote controller is arranged to providecontrol commands to said location controller automatically in accordancewith monitored meteorological conditions (rainfall, temperature, airhumidity, etc), and/or in response to manual override commands.

[0037] The location controller may provide the irrigation program, theremote control command receiver, and the default setting means, all aspart of a single controller unit. Alternatively, the location controllermay be provided as a combination of units. For example, the remotecontrol command receiver and the default setting means may beelectrically connected to an existing standard onsite irrigation programcontroller.

BRIEF DESCRIPTION OF THE DRAWINGS

[0038] By way of non-limiting example, the invention will now bedescribed with reference to the accompanying drawings, in which:

[0039]FIG. 1 schematically illustrates the system of the presentinvention; and

[0040]FIGS. 2a and 2 b illustrate default switching positions inaccordance with the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

[0041] The embodiment described below enables a plurality of devices tobe automatically placed in whichever default operating mode (normallyclosed or normally open) is required or is appropriate for theparticular situation over the course of time.

[0042] The invention will be described below with respect to anirrigation system, but it is to be understood that this is merely by wayof exemplification, and in no way to be seen as limiting the potentialsphere of application of the invention.

[0043] Programmable irrigation controllers, to schedule and manage theirrigation of specific areas to be irrigated, such as parks, gardens andsports facilities, without the need for human intervention, aregenerally known in the art. A single controller can store one or moreirrigation programs for a plurality of valves spread over a number ofzones associated with that location. The irrigation programs are set asa function of various measured characteristics of the zones to beirrigated, such as the root zone depth, soil texture, etc, the programfor a particular valve thus providing an optimum irrigation event forthe associated zone.

[0044] It is also known to provide a programmed local controlling devicewhich is able to receive command signals in accordance with monitoredmeteorological conditions, so that the programmed events may beoverridden on command. For example, if rain is detected in a particularzone at which an irrigation event is underway, the irrigation event canbe discontinued.

[0045] The system may be a true distributed system, with a centralcontroller in communication with a great many local controllers carryingout a variety of functions and spread over a large total area, thecentral controller receiving and processing weather station assets,governing and monitoring the operation of the local controllers, andrunning modeling and prediction algorithms, with the objective ofproviding the most beneficial irrigation regime at every zone in thearea. In Applicant's Micromet™ system, the system operates over theInternet, which greatly enhances reliability, and the communication withthe local controller is accomplished by way of a wireless radio link,the command data received by an appropriate antenna/receiver at thelocal controller.

[0046] The implementation of commands received from the remotecontroller is achieved by control of the output of the local controller.This is performed by means of one or more switch relays located in theelectrical circuit between the controller and the solenoids of theirrigation supply valves (the irrigation sub-system). The switching coilof a relay is energised and de-energised to control the device withwhich it is associated, in order to achieve the local activity, (or lackthereof) required. As a general rule, the controllers in a system ofthis type are set to a ‘fail wet’ default, meaning that in the absenceof a remote override command (due to any unreliability in the remotecontroller or in the communication system) they are set to provide anirrigation event, because an over-watering of a zone is generallypreferred to an under-watering. However, this situation is far fromideal, as will be explained in further detail below.

[0047] If the relay within the controlling device is wired into thesub-system using the normally closed terminals of the relay, then unlessa signal is received by the device causing the coil to be energised bythe device, the wired-in sub-system will be active for that controlperiod (typically, but not necessarily, one day). This operating modecan be referred to as ‘fail active’, meaning that the default conditionof the sub-system is an active or operating mode.

[0048] If the relay within the controlling device is wired to thesub-system using the normally open terminals of the relay, then unless asignal is received by the device causing the coil to be energised by thedevice, the wired-in sub-system will be inactive for that control period(ie, the program stored in the local controller will not operate on thecontrol valves and they will remain closed. This operating mode can bereferred to as ‘fail inactive’, meaning that the default condition ofthe sub-system is an inactive or non-operating mode.

[0049] The following scenario will make the advantages of thesecontrasting operating modes clear with respect to the primary factors tobe considered, ie the circumstances of the system being controlled, thetime of year, and the time of day.

[0050] Consider that a particular sub-system being controlled by thedevice incorporating the relay is an irrigation system. This irrigationsystem is operated by a standard electronic controller of the typetypically used to control the irrigation on an irrigated public openspace. An example of such an area is a public park within a major city,with irrigated turf areas, managed by a local government authority suchas the local council.

[0051] The device typically exerts control over operation of theirrigation controller in one of two ways:

[0052] 1. The relay of the device is wired across the controller's valvecommon wire so that the electrical circuits to the valve solenoids canbe made or broken by the operation of the relay; or

[0053] 2. The relay of the device is wired across the controller'ssensor port such that valve operation is possible given electricalcontinuity between the terminals of the sensor port.

[0054] In either case, if the relay of the device is connected to thecontroller using the normally closed terminals of the relay, then on anyand every day that a signal is not received resulting in an energisingof the relay's switching coil, the irrigation controller will apply anirrigation event. If such a signal is not received then the sub-systemwill be active (the ‘fail active’ configuration).

[0055] Conversely if the relay of the device is connected to thecontroller using the normally open terminals of the relay, then a signalresulting in an energising of the relay's switching coil, must bereceived whenever the irrigation controller is to apply an irrigationevent. If such a signal is not received then the sub-system will beinactive (the ‘fail inactive’ configuration).

[0056] It will be readily appreciated that if a signal failure occursthere will be a fundamental difference in the result between the twosystems.

[0057] In summer, in most circumstances, an occasional additionalirrigation is not likely to be especially problematic. However, inwinter, it can be a major problem, as it may lead to excessivewaterlogging and, should the area under management to be a sports arena,then a game might be washed out, or the irrigation system actuallydamaged by the operation.

[0058] Similarly an occasional unintended irrigation may not beproblematic early in the week, but on a Friday or Saturday in particularmay conflict with public use of the park. Should the area undermanagement be a sports arena then operation on a Friday, Saturday orSunday is significantly more likely to conflict with or affect sportingactivity.

[0059] Therefore a general summary of the advantageous states relatingto the operation of a sub-system in irrigated public open space areasmay typically be as follows: Summer Winter Sunday fail active failinactive Monday fail active fail inactive Tuesday fail active failinactive Wednesday fail active fail inactive Thursday fail active failinactive Friday fail inactive fail inactive Saturday fail inactive failinactive

[0060] To achieve the optimum basic operating modes as summarised anddefined above, sites would have to be continually visited and undergowiring modification in order to alternately wire the connections betweenthe relay within the device and the sub-system using respectively, thenormally open or the normally closed terminals, as required havingregard to the time of the year and the day of the week.

[0061] In particular, as indicated above, the ‘fail inactive’ state onFriday and Saturday evenings in summer is especially important in thecontext of sports turf surfaces, as explained above.

[0062] The invention provides a method and system for achieving thisconveniently, without requiring site visits ordisconnection/reconnection of wiring systems.

[0063] With reference to FIG. 1, the onsite components of a system inaccordance with the invention include a programmable irrigationcontroller 10, a wireless receiver unit 20, and five electricalsolenoids V1-V5 controlling respective irrigation valves in that localarea. Unit 20 may be incorporated into controller 10, or may (asillustrated) be a separate unit, ‘retrofitted’ to a conventionalirrigation sub-system.

[0064] Controller 10 includes a power source (not shown), a transformerT, a power bus 11, and five independent switch devices 12 managed by acentral programmable controller processor (not shown). Controller 10also provides a common connection C connecting to a common bus forsolenoids V1-V5. Each solenoid is wired to a respective switch device12, and the controller program is thus able to control the timedswitching of each valve solenoid, by selective connection of the linesto respective solenoid valves with power bus 11.

[0065] Unit 20 is wired into common line C as shown in FIG. 1, and thusprovides an override for the output of controller 10. Unit 20 includesan antenna 21, which provides a signal input to a receiver/processor 22,which controls a relay switching module 23 in accordance with thereceived signals. Applicant's Micromet™ irrigation device works in thisway, receiving remote command signals from a central Micromet computer.

[0066] Two possible configurations of switching module 23 are shown inFIGS. 2a and 2 b, respectively ‘fail active’ and ‘fail inactive’. In‘fail active’ mode, the relay coil 24 is normally energised due toelectronic switch 25 being dosed, and common connection C is thusnormally unbroken. Signals received at receiver 22 result in an openingof electronic switch 25, a resultant de-energising of coil 24, and abreaking of common connection C. With this wiring configuration, in theabsence of a received signal, the irrigation program in controller 10 iscarried out. In ‘fail inactive’ mode, the opposite outcome is achieved.In the absence of a received signal, electronic switch 25 is open, coil24 is unenergised, and common connection C remains open. With thiswiring configuration, in the absence of a received signal, the output ofcontroller 10 is not carried out at the irrigation valves.

[0067] This desirable result can be achieved by either a software or ahardware solution.

[0068] In the software solution, relay 23 in the device defaults to oneof two modes. In programming this software device, an instruction set isprovided to set switch 25, in order to control how the device willfunction, and thus whether it is to fail inactive or active, in a timedependent manner. Additional instruction to control the position ofswitch 25, and thus define the default position of relay 23 (ie whetherit is to fail active or inactive at any given time) can be provided fromtime to time if required, as part of the remote commands issued by theremote controller. In other words, the locally stored time-dependentdefault mode setting program can be updated from time to time inresponse to commands received from the remote controller.

[0069] In one example of a hardware solution, relay 23 is provided byway of a bi-polar stable relay. The circuitry changing the wiringconfiguration from normally closed to normally open is connected toappropriate terminals of the bi-polar stable relay. Instruction as towhether it is to fail active or inactive can be sent from the remotecontroller from time to time as required, causing the bi-polar stablerelay 23 to change state.

[0070] While this invention has been particularly shown and describedwith reference to preferred embodiments thereof, it will be understoodby those skilled in the art that various changes in form and details maybe made thereto without departing from the spirit and scope of theinvention as defined in the appended claims

[0071] The invention has been described with reference to an irrigationsystem, but it is to be understood that it is capable of application inmany other spheres. For example, it may be used in controlleddistributed lighting systems, or in controlled security applicationssuch as door and gate locking systems.

[0072] The word ‘comprising’ and forms of the word ‘comprising’ as usedin this description and in the claims does not limit the inventionclaimed to exclude any variants or additions. Modifications andimprovements to the invention will be readily apparent to those skilledin the art. Such modifications and improvements are intended to bewithin the scope of this invention.

1. A method of control for a distributed event system, providing controlof events at one or more locations, each location associated with aprogrammable location controller able to cause or permit a prescribedevent to be carried out at that location, the location controller ableto receive control commands from a remote controller, each locationcontroller having at least two default settings to govern implementationof said prescribed event in case of non-receipt of commands from saidremote controller.
 2. A method according to claim 1, wherein saiddefault settings are automatically selectable in accordance with one ormore parameters, for example, in accordance with time.
 3. A methodaccording to claim 2, wherein the selection of the location controllerdefault setting is made in accordance with the season of the year and/orthe day of the week and/or the time of the day.
 4. A method according toclaim 1, wherein the distributed event system comprises an irrigationsystem, and each location controller is operatively connected with atleast one electrically operable water valve to control water supply toan area associated with that location, each location controllerincluding an electrical switch relay having two selectable defaultpositions, ‘fail-open’ and ‘fail-closed’.
 5. A method according to claim4, control commands received from the remote controller by said locationcontroller are provided in accordance with monitored meteorologicalconditions.
 6. A method according to claim 4, wherein the defaultposition for a location controller is established as part of the powerconnection configuration to the electrical terminals of the at least oneelectrically operated water valve.
 7. A method according to claim 6, thepower connection configuration being selected under software control,the software being remotely programmable from the remote controller tovary the functional relationship between the selection of the defaultsettings and said one or more parameters.
 8. A method according to claim6, the power connection configuration being selected under hardwarecontrol.
 9. A method according to claim 8, the power connectionconfiguration including a bi-polar stable relay.
 10. A programmablelocation controller for a distributed event enabling system controllingevents at one or more locations, the controller able to cause or permita prescribed event to be carried out at a respective location, thecontroller arranged to receive control commands from a remotecontroller, wherein the controller has at least two default settings togovern implementation of said prescribed event in case of non-receipt ofcommands from said remote controller.
 11. A controller according toclaim 10, including means to select said default settings in accordancewith one or more parameters, for example, in accordance with time.
 12. Acontroller according to claim 11, including means to select the locationcontroller default setting in accordance with the season of the yearand/or the day of the week and/or the time of the day.
 13. A controlleraccording to claim 10 for use with an irrigation system as saiddistributed event system, the controller operatively connectable with atleast one electrically operable water valve to control water supply toan area associated with that location, the controller including anelectrical switch relay having two selectable default positions,‘fail-open’ and ‘fail-closed’.
 14. A controller according to claim 13,including a power connection configuration to the electrical terminalsof the at least one electrically operated water valve whichconfiguration provides the means to establish the default position. 15.A controller according to claim 14, including software to establish saidpower connection configuration, and including means to allow remoteprogramming of said software from a remote controller to vary thefunctional relationship between the selection of the default settingsand said one or more parameters.
 16. A controller according to claim 14,including hardware circuitry to provide said power connectionconfiguration.
 17. A controller according to claim 16, said circuitryincluding a bi-polar stable relay.
 18. A programmable irrigation systemincluding the programmable location controller of claim 13 and aplurality of electrically operable water valves operativelyinterconnected therewith in order to control water supply to an areaassociated with that location.
 19. A distributed event system includinga plurality of controllers according to claim 13, including means toprovide control commands to said location controllers automatically inaccordance with monitored meteorological conditions.